1. The level of pain catastrophizing;
2. the level of pain-related fear;
3. the level of disability.

- Secondary outcome

N/A

- Timepoints

1. The first measurement is at the beginning of the two-week baseline period;
2. the second measurement is at the beginning of the treatment phase;
3. the third measurement is at the end of the treatment phase;
4. the last measurement is at follow-up, six month after the last treatment session.

Today, there are numorous studies in which the important role of pain catastrophizing in relation to various pain-related problems such as pain intensity, depression, and disability is demonstrated (for an extensive review see Sullivan et al., 2001). Given this relationship, pain catastrophizing seems an important starting point in the treatment of chronic pain. Pain catastrophizing is about an extremely negative way of thinking about pain and its possible consequences in which threat and fear of pain are important ingredients. Not surprisingly therefore, pain catastrophizing is closely related to fearful cognitions about pain. Given this cognitive nature of pain catastrophizing, it is obvious to use the principles of cognitive therapy in its treatment. In a meta-analysis of rct's of cognitive behavior therapy for chronic pain, Morley et al. (1999) found that treatments based on the principles of cognitive behavior therapy were effective compared to waiting list conditions. Also, there are two studies that showed that patients with chronic low back pain treated with cognitive behavior therapy improved on a number of outcome measures (such as disability, pain intensity, depression and pain behavior). Moreover, this improvement was mediated by a reduction in pain catastrophizing (Smeets et al., 2006; Spinhoven et al., 2004). Remarkably, the level of pain catastrophizing decreased in various treatment conditions and by using different techniques, even though none of these techniques were specifically targeted at the reduction of catastrophizing (Smeets et al., 2006; Spinhoven et al., 2004).
In this study we want to examine whether a treatment specifically aimed at reducing pain catastrophizing is effective in treating patients with chronic pain who catastrophize highly about their pain. In this respect the study fits with the idea that treatments for chronic pain may be improved by tailoring them to the specific characteristics and needs of the patient (in this case patiets who catastrophize highly about their pain).
We hypothesize that, compared to a baseline period, the treatment period will involve a reduction in the level of pain catastrophizing, fear of pain, and level of disability.